Combustion equipment of rocket motors



Jan. 5, 1954 s. ALLEN ET AL 2,664,701

COMBUSTION EQUIPMENT OF ROCKET MOTORS Filed Aug. 7, 1951 1 r h k 27/ 28 34 FICZ INVffi/TORS 5". ALLEN E. 0.11. ANDREWS y nrrm Patented Jan. 5, 1 954 COMBUSTION EQUIPMENT F ROCKET MOTORS Sidney Allen and Edward G. D. Andrews, Coventry, England, assignors to Armstrong Siddeley Motors Limited, Coventry, England Application August 7, 1951, Serial No. 240,725

Claims priority, application Great Britain September 8, 1950 Claims. (Cl. 6039.09)

This invention relates to a rocket motor of the kind in which liquid propellents are burnt or dissociated, and having combustion equipment including a jacketed combustion chamber through the jacket space of which one of the propellents is circulated for cooling the combustion chamber before entering the latter. Each of the propellents is, of course, supplied under pressure, either by means of a pump, or by means of pressure applied to a reservoir for the propellent.

The main object of the invention is to prevent pressure generated by evaporation or expansion of the propellent in the jacket space from causing the propellent to flow into the combustion chamber after the motor has been shut down. Otherwise, when the motor is shut down, the resulting evaporation or expansion of the propellent in the jacket space can cause a flame to be present in the combustion chamber for some time after the motor has shut down, or it can cause an accumulation of propellent in the chamber which gives rise to roughness or explosion on restarting the motor.

According to the invention, the jacket space is connected to a pressure-responsive dump valve which is biased to the open position and closable by an applied pressure which is available only while the motor is operating; whereby, on shutting down the motor (in which case the pressure applied to the dump valve falls so as to allow it to open), the jacket space is vented so as to prevent pressure generated by evaporation or expansion of the propellent in the jacket space from causing the propellent to flow into the combustion chamber.

Preferably the dump valve is connected to the underside of the jacket, the propellent which is circulated therein passing through a check valve on its way from the outlet end of the jacket space to a spray nozzle leading to the combustion chamber. Furthermore, when the propellent which is circulated in the jacket space is delivered thereto by means of a pump, the latter may also be directly connected to the dump valve so as to apply operating pressure thereto, while the pump is Working, for closing the dump valve.

In the accompanying diagrammatic drawing:

Figure 1 is an elevation of a combustion equipment, of a rocket motor, with a dump valve, according to the invention, attached thereto; and

Figure 2 is a sectional elevation of the dump valve to a much larger scale, Figure 3 being a fragmentary section, to the same larger scale, of the part of the casing of the combustion equipment to which the dump valve is to be attached.

The invention is shown as applied to combustion equipment of the kind including a main combustion chamber i l in which the propellents (for example, liquid oxygen or other oxidizer and a liquid fuel such as a mixture of methyl alcohol and water) are burnt.

The combustion chamber is provided with a jacket l2, and one of the propellents (e. g., the liquid fuel) is circulated through the jacket space l3 before being burnt. This propellent, delivered by a pipe [4 to the jacket space, is, after circulating round the latter, delivered by a pipe [5 through a check valve, indicated at [6, to a device IT for spraying the fuel into the combustion chamber. The other propellent (e. g., the oxidizer) is delivered along a pipe, part of which is indicated at it, to the spray device H.

In the present instance the fuel is supplied from a reservoir 20 by a pump, indicated at 2|, to the pipe I l; and, as will be well understood, there will be an appropriate control valve (not shown) in the pipe M.

The dump valve 24 is formed with a passage 25 (Figure 2) adapted to be connected to the underside of the jacket space by means of the hollow nipple 26. The dump valve has a vent 27 which is placed in communication with the passage 25, i. e., with the jacket space [3, when a valve member 28 of the dump valve is raised off its seating 29, as shown in Figure 2. A spring 30 acts on a plunger 3| fast with the valve member 28 to bias it to the open position, the plunger working in a cylinder 32.

The end of the cylinder remote from the passage 25 has an inlet 34 which is shown in Figure 1 as being directly connected by a pipe 35 with the outlet of the pump 2|. Thus, when the pump is started up and begins to deliver fuel, the pressure applied to the plunger 3 lcloses the valve member as long as the rocket motor is operating.

As previously stated, however, when the motor is shut down, in which case the pump 2| ceases to deliver fuel allowing the valve member 28 to move to its open position, the dump valve then vents the jacket space 13, and in this way pressure which would otherwise be generated in the jacket space, by the evaporation or expansion of the propellent therein, is prevented from opening the check valve 16 and allowing the propellent to flow into the combustion chamber, whereby to avoid the objections above-mentioned.

What we claim as our invention and desire to secure by Letters Patent of the United States is:

1. A rocket motor, of the kind in which liquid 3 propellents, supplied under pressure, are burnt or dissociated, including a jacketed combustion chamber, a supply pipe for delivering one of the propellents to the jacket space to be circulated therein for cooling the combustion chamber before entering the latter, a pressure-responsive dump valve connected to said jacket space, said dump valve biased to the open'position; means comprising a check valve for conveying said one propellent from said jacket space to the combustion chamber, and a pipe branching'from"saiid'f supply pipe and applying the static pressure of.

cooling the combustion chamber, a spray'devi'ce' in the chamber, a pipe connecting thejacket' space to said spray device, a check valve 'for controlling the flow of said one propellent from-said jacket space to-said' spray device, a pressure responsive dump valve connected tether-jacket space, said dump valve biased to the open posi-'- tion, and a pipe branching from said supplypipe and applying the static pressure of said pump to said dump valve whereby to close"it' while said pump is operating.

4. Arocket motor, of the kind in'whichliquid propellents, supplied under pressure; are burnt" or dissociated; including ajacketed combustion chamber, means-for supplyingonerof the propellents under pressure to the jacketspace, conduit" means connecting the jacketspacato'the' com-- bustion'chamber, a check valve in said-conduit means biased to closed positionand adapted to be opened by the pressure in-thejacket space when said supplying means is operating, a pressure-responsive dump valve connected to the jacket space and to said supplying means, whereby the dump valve is closed during operation of said supplying means, and means for biasing said dump valve to open position when said sup plying means is not working, whereby said one propellent is drained from the jacket space.

5'. A rocket motor of the kind in which liquid propellents supplied under pressure are burnt or dissociated including a jacketed combustion chamber, a supply pipe, pump means for supplying one of the propellents through said supply pipe-totlie jacket space for cooling the combustion chamber, conduit means connecting the jacket space to the combustion chamber, a check valve in said conduit means and adjacent to the point of fuel injection to said combustion chamber and biased to closed position and adapted to be opened by the pressure in the jacket space when'said'pumpis operating, a pressure-responsive dump valve connected to the'jack'et space,

means for conducting'said one'propellent under pressure from said'pump means to said dump valve for maintaining saiddump valve inclosed' position during operation of said pump means,

and resilient means for immediatelyopeningsaid dump valve upon cessation of operation of said pump means.

SIDNEY ALLEN EDWARDG. D. ANDREWS.

References Cited in-the fileof this patent UNITED STATES PATENTS Number Name Date 2,341,758 Carpenter Feb. 15, 19 14 2,446,013 Kuyper July 27, 1948 2,508,260 Holley May 16,1950 2,510,571 Goddard June 6,v 1950 2,547,959 Miller Apr. 10, 1951 2,573,724 Neal Nov. 6, 1951 2,578,501 Boosinger Dec. 11,1951 

